Ecology, economic botany and conservation of Diploknema butyracea in Nepal

Abstract

Diploknema butyracea (Roxb.) H. J. Lam, butter tree, locally known as Chiuri, is a medium to large-sized deciduous tree widely distributed on the south-facing slopes in the sub-Himalayan region from 200 m to 1500 m. This is an economically valuable, nutritionally important, ecologically slow-growing, and culturally integrated multipurpose tree species. The tree is culturally connected with an ethnic minority group, Chepang, in central Nepal. We systematically reviewed over 102 primary research studies, review papers, and grey literature, along with nine field visits, three each in western, central, and eastern Nepal to collect the population and ethnobotanical data of Chiuri. Additionally, government forest officials, forest user groups, and local communities of 62 districts were consulted to collect and verify the information on distribution, use, and conservation. The interrelationship of ecology and ethnobotany of Chiuri was found to be positively associated. This tree was reported to be grown in 58 districts, abundant in central and western Siwalik and mid-hills. The ethnobotanical use reports of Chiuri used by 26 ethnic groups were recorded from 22 districts. Among the groups, Chepang has intensive use reports and conserved this multipurpose tree since time immemorial. Ethnotaxonomically, four types of Diploknema species were reported by Chepang communities, whereas the national botanical records and molecular analyses have yet to confirm the types. As the species complements the livelihood, traditions, history, socio-culture, folklore, and household economy of Chepang people, we supported the argument that the D. butyracea is a cultural keystone tree species (CKTS) in Nepal for Chepang people. Further research on socio-cultural, ethno-ecological, and morpho-molecular attributes is urged for cultural integrity, biodiversity, and bioprospecting.